ok so heres my problem. my A/C works when it works. when i have the fan speed on 1 the compressor light kicks on and does infact engage, however when i turn the fan speed to 2, 3, or 4 the light goes off but it will blow the cold air that has beeen building from having it on the number 1 speed for about ten or so seconds then the air gets hot. however on the other hand EEEEVERY once in a while it will stay on and blow just like it should, but that is very very rare. so, with that said, everyone has told me there is a leak, or the compressor isnt charged. well there is no leak, and the compressor is charged, i have taken it to two different mechanics so we have to assume that they are right. one did tell me that since it is charged and there are no leaks it has to be the control box, or whatever you call it is bad, you know the thing in the dash with the ***** and buttons for the A/C.... so i went to a local junk yard and found two different VUE's that still had that part in it, i took it out of both cars and put both of them in mind and the problem still existed. now granted i understand the parts came from a junk yard, but the odds of three different parts from three different cars doing the same exact thing is very very strange so i put the one i had back in. so at this point i am at a stand still because its not that switch, the compressor is charged, there are no leaks, so i have no clue what else to do. and im ruling out that the compressor is bad because it engages and compresses on low, but thats it, and it does sometimes work on other speeds too. i was told there is a resistor in the evacuator box that is supposed to change resistance or something as the fan changes speed that can be bad. so it cant be a fixed resistor, it has to be some kind of rheostat or something right? and where the hell is the evacuator box and is this a good idea? any thoughts would be greatly appreciated because its very hot!!!!!!!!!

 

By the terminology you use it seems you are not a HVAC mechanic . right ?
But one thing that comes to mind for me first by your discription of the problem I thought of the switch. You changed that with "used" parts. You are probably right, not likely all are bad. Now you should check the "relay". I can't tell you where it is, but I bet you can find it under the hood in the electrical box with fuses and relays.
you need to change it out with a known good part.
That is where I would go next.

 

I suspect you are referring to the HVAC blower speed resistor. Its basically three different resistors all in series (one after the other). In fan position one, the power runs through all three resistors. As you switch to positions 2, 3, and 4, the switch bypasses one or more of the resistors, until in position 4, the power goes directly to the blower. The A/C compressor itself is switched on and off by two relays, one in the passanger cabin, and the other under the hood. These relays are controlled by the Powertrain Control Module (PCM) and the Body Control Module (BCM).

For me, the next step would be to swap out (replace) the relays....

 

i will respectfully disagree with OA on the next step.
If either of the relays were bad, the A/C "on" command from the PCM would never be received and the compressor would never turn on.

IF the resistor pack is a series-type per OA's description, since it works on the "1" setting (which is with all resistors in series so highest resistance = lowest current to motor = lowest fan speed), one would think the other resistors are good. So I would have to default to guessing that the resistor pack actually has 4 resistors not in series, and the grounds for the other three are gone.....but I'm guessing and am far from a Vue expert

So I would say go after the resistor pack

 

Sometimes
Derf makes so much sense
it is scary!

 

ok, no i am not am HVAC mechanic by any means, but i am an electrician so i have a knowledge of what should do what basically. i have a question... i pulled the resistor under the dash yesterday and i left it out. when i was driving home just for ****s and giggles to see what would happen i turned the air to "1" and the compressor indicator light(the little snow flake light) came on, and when i went to position "2, 3, or 4" the light went off just like it would any other day. so my question is, is the resistor under the dash tied in to the compressor or is it just for the fan motor that controls the amount or speed of the air coming out? because (with the resistor in of course) when i switch from 1 to either 2,3,or 4, the air does in fact come out faster in proportion to where the know is. so that leads me to believe that the resistor is working. now, i agree with the relay maybe, i will look for it and see if i can get one and change it and also there is a pressure switch to right? would that have any thing to do with my problem?

 

The resistor pack is strictly for adjusting the speed of the blower inside the passanger area of the vehicle -- it has no bearing whatsoever on the compressor

 

resistor = fan speed
relay = compressor on ( and could be intermittent with burnt contacts)

I just love to tear those little buggers apart and "confirm" they are faulty ..... right AFTER I install a new one.